This invention relates to technology that enables a primary device connected to a primary network and a secondary device connected to a secondary network to communicate by means of address conversion.
A Network Address Translator (NAT) device is used as a device to enable communication between private and global networks.
As with, for example, Real Time Streaming Protocol (RTSP), there are times when information is included that is considered necessary when conducting IP address communication for the payload part which stores application data. When protocol such as this is used, the information converted by a NAT device differs from that stored in the payload part and there are times when problems can arise with communication.
Technology for converting an IP address included in the packet payload part is described in Japanese Laid-open Patent Publication No. 2005-167301 (Document 1).